Democrats considered his seat vulnerable since it had been held for 41 years by Democratic Rep. Dave Obey, who retired in 2010. Outside groups spent heavily to try to oust Duffy.

But he benefited from redistricting, which moved GOP-leaning areas including Vilas and St. Croix counties into the district, which roughly spans the northwest quarter of the state.

Duffy also had more money, having raised $2.4 million compared to Kreitlow's $1.2 million as of mid-October.

Duffy, a former district attorney, is also a professional lumberjack from Ashland who appeared on MTV's "The Real World" in the 1990s. He sits on the House Financial Services Committee.

"I am so grateful for your support and for what we were able to accomplish together," Kreitlow said in a statement. "I will never forget that, or the people of Wisconsin we have met throughout this campaign. I congratulate Congressman Duffy and wish him and his family the best of luck."